The Fitch Monoclonal Antibody Facility is a shared resource with two major goals: (1) to provide investigators in the University of Chicago Cancer Research Center and other University of Chicago investigators with a highly accessible and economical means for developing high-quality monoclonal and polyclonal antibodies for the purposes of clinical or basic research using proven methodologies; (2) in addition we also work closely with the investigators to develop novel approaches for generating quality monoclonal antibodies that will be useful reagents in diagnosis and therapy. The facility presently provides investigators with guidance and technical expertise in developing reagents that are well suited to their specific research needs. We also provide services designed to augment the usefulness of reagents developed here or elsewhere, including hybridoma subcloning, monoclonal antibody isotyping or quantitation, ascites production or other methods of generating moderate levels of antibody for research proposes. We are collaborating with the Animal Resources Center in the development of efficient in vitro methods of antibody production. Monoclonal antibodies have become essential tools in the interdisciplinary approaches to biological research, and the variety of applications requiring monoclonal antibodies have continued to expand as this technology has developed. Monoclonal antibodies remain very powerful tool for immunophenotyping cells in the study of cancer, transplantation, and immunology. There usefulness has been extended in the biochemical analysis of normal and abnormal functions of these and other cells. Furthermore, monoclonal antibodies are pivotal elements in many experimental and clinical strategies for the diagnosis and treatment of certain diseases. Our ability to derive and produce monoclonal antibodies provides a highly accessible resource which meets a growing demand for such reagents in the Cancer Center research community.